On Monday, Sir Roger Norrington will conduct the Boston-based Handel and Haydn Society in its Proms performance of Haydn's The Seasons. The society is not only among the oldest performing arts organisations in America; it is older than most of the great European orchestras. When it was founded in 1815, Haydn had been dead for only six years. It gave the American premiere of his Creation in 1819 and attempted, albeit unsuccessfully, to commission a symphony from Beethoven. The match between the orchestra and Norrington is well made. In its institutional memory, the society can make a convincing claim to know what Haydn actually sounded like when he was a contemporary musician. So can Norrington, who was appointed as its artistic adviser at the start of the 2006-07 season.

As a leading figure in the period music movement from the early 1960s to the present day, Norrington has been a vociferous advocate of musical authenticity. But his quest has gone beyond using period instruments and into the more contentious areas of tempi - he asserts that much music is played slower than the composers intended - and technique, on which battleground he has waged a sometimes lonely war against the "modern drug" of vibrato.

"The fact is orchestras didn't generally use vibrato until the 1930s," he explains. "It is a fashion, like smoking, which came in at about the same time. Smoking is now going, so maybe vibrato will too. Imagine it: a vibrato-free world." Norrington's argument is not that vibrato "might not be a wonderful thing - it often is in jazz - but if Brahms expected to hear a particular sound, I want to know what that was. Or at least I want to hear it a few times before deciding that it is rubbish. But what I have discovered, all the way from Monteverdi to Mahler, is that when music is played as it should be, the sound is wonderful, the expression is wonderful and the instruments match together."

Norrington's evangelical journey has taken him through four centuries of music and, over the past decade in his work with the non-period-instrument Stuttgart Radio Symphony Orchestra, into the geographical as well as musical heartland of the core repertoire. "Doing Monteverdi, or even Haydn, in an authentic manner seemed to be one thing," he says. "But Beethoven? Berlioz? Wagner? And now Mahler? I was never sure that modern orchestras would ever be able to play like this. I thought it might have been the preserve of chamber or historical orchestras. So to discover that they, too, have the chance to play the real Brahms, the real Bruckner, is terrifically exciting. They may not all want to, but they can. Most people over the age of 70 have either retired or are repeating themselves. So to have found, at the end of my career, one more thing to say has been the most extraordinarily rewarding thing."

Norrington was born in 1934, the son of Edith and Arthur Norrington, Oxford vice-chancellor and originator of the Norrington league table, which ranks Oxford colleges. Music was important to the family. His parents had met while singing Gilbert and Sullivan in an amateur production. His mother was a good pianist, and the young Roger played the violin, was a boy soprano and eventually a tenor. "One of my earliest musical memories is of seeing HMS Pinafore, which I thought was fantastic, though I suspect it might be a bit too twee for children these days."

After being evacuated to Canada during the war, he returned home to Oxford, aged 10, and found "these musty old records. Some of the Beethoven was a bit difficult at first, but the Bach Brandenburg No 6 was wonderful. I played it a hundred times a day. If this was so-called serious music, then it was for me." He saw Furtwängler conduct the Berlin Philharmonic on their first postwar visit to Britain and begged his parents to stay for the whole four-and-a-half-hour performance of Bach's St Matthew Passion in which they were singing. "There was lunch halfway through in those days. You can guess why: they played it much too slow!"

Norrington was sent to the Dragon school in Oxford, where he auditioned for the chorus in Iolanthe and was given the lead. "I realised I had some sort of gift, and when my voice broke I had a decent tenor voice. But I thought I would be like my parents and spend my life doing music in my spare time."

So Norrington went off to do his national service as an RAF fighter controller in Bournemouth, read English at Cambridge, and took a job at Oxford University Press (OUP), where he published religious books. For the next six years, until he was 28, he says, he put in professional hours as a musician without being paid. "I sang in a couple of choirs, played in an orchestra or two, played quartets. So every weekend and most evenings were full of music. I'd conducted a little in my last year at Cambridge, so I did a bit of that, too."

The breakthrough as a conductor came when he realised he knew enough about the music "to have something to say. The nightmare is to be in front of an orchestra who know the music better than you do and you have nothing to say. But from 18 to 28, I had been watching other conductors, sometimes as a part of a choir or orchestra. I was inspired by Colin Davis, I sang for Giulini and saw Furtwängler. If you take it seriously, you can pick up an awful lot."

Norrington says that at this early stage he didn't have an agenda as to how music should be played beyond doing it as well as possible. But in the early 60s, he "stumbled upon" the then relatively unknown German 17th-century composer Heinrich Schütz. "This brilliant range of church music had just been published in Germany and I wanted to perform as much of it as possible." Norrington formed the Schütz Choir and, in 1962, put on a groundbreaking London concert with some young professional musician friends.

"The discovery of Schütz prompted the question of how the music should be performed. There was a tradition of Bach performance, but not for Schütz. I realised that you couldn't sing it like you sang everything else. Then period instruments began to re-emerge, and with people like Christopher Hogwood there was eventually something of a frenetic whirl of period music-making activity in London."

At the time of that first Schütz concert, Norrington was still a publisher and was soon afterwards sent to east Africa by OUP. The six months away gave him "time to think", and when he came home he took up the offer of a place at the Royal College of Music, made by the principal, who had seen his first Schütz concert. He studied conducting under Adrian Boult, played percussion in the orchestra, learned composition and the history of the orchestra. "It was wonderful, as I could pretty much do what I liked without having to take any exams. I still haven't taken a music exam. I don't even have grade one in the recorder. It's interesting that one was allowed to do that."

The belated move to turning pro eventually came when a friend was about to take the same step. "I asked him how would he feel if he failed. He asked how I would feel if I never tried. That put me on the spot, and I jumped. And, thank God, I never looked back."

Norrington lives with his second wife, the dancer and choreographer Kay Lawrence, near Newbury in a large red-brick Victorian house that wouldn't be out of place in a Merchant Ivory adaptation of EM Forster. Their son, Tom, is a music scholar at Eton and is following the family singing tradition, having recently sung the part of the boy, Yniold, in the Covent Garden production of Pelléas et Mélisande. "I was as nervous as a kitten watching him," confesses Norrington, who, from his garden, can point in the direction of the homes of Tippett and Finzi - and Lloyd Webber - as well as, "a bit further", Elgar. He spends half the year at home and half away working all over world. It has been his routine since being diagnosed with skin cancer and a brain tumour in the early 90s. "I have an amazing doctor in New York, and thanks to the diet and the pills" - he takes 120 a day - "my health is very good. I wasn't ever in terrible pain, but I did take time off. And while everyone talks about sitting on a beach or playing golf ... work is the best thing, as long as there's not too much of it."

In 1972, the Schütz Choir was wound up "at what seemed a natural point to move on", the 300th anniversary of his death. Norrington then undertook the first period-instrument Messiah - in Handel's church in London's Hanover Square - and Monteverdi's Vespers. There was a growing pool of enthusiastic players and singers in London, and in 1978 he founded the London Classical Players. Over the next 20 years they began to move meticulously through the repertoire. "When we began a new composer, I always called the best scholars to ask about how the music had been done and we never moved on until we thought we'd got it right."

His recordings of the Beethoven symphonies in the mid-80s were variously hailed as revelatory or dismissed as "implausibly fast". "It's played at that speed because Beethoven wrote it that speed," says Norrington. "And in the past 20 years, even the mainstream speeds of Beethoven and Mozart have definitely increased. There were more rows about Mendelssohn and Wagner. Yes, our Tristan und Isolde prelude was a shock to people, but not because it was wrong; rather, because everyone else was too slow. There have been more rows about Mahler."

Norrington's newly released "pure tone" recording of Mahler's second symphony with the Stuttgart orchestra has provoked a typically polarised response. He describes it as his "last hand grenade". "After Mahler, music was played with vibrato. But my story, from 1962, has been one of knocking down wall after wall and seeing what happened. So to discover right at the end that these great traditional European and American orchestras can be part of it as well has been wonderful. Now even they are beginning to realise you don't need to put vibrato on everything, like sugar. I know that I'm still the only conductor that really asks them not to. And that many great musicians simply don't know why they should even reconsider what they essentially learned in college. But I can't live without trying to see the skull beneath the skin. In the end, I know this project might still fail, or be shelved for 30 years. So if, on the day I die, the world is playing without vibrato, of course I will be delighted. But even if they aren't, I'll still be delighted because at least I did."